Journal
ASTRONOMICAL JOURNAL
Volume 144, Issue 3, Pages -Publisher
IOP Publishing Ltd
DOI: 10.1088/0004-6256/144/3/72
Keywords
binaries: close; binaries: spectroscopic; stars: individual (TYC 2930-00872-1)
Categories
Funding
- Vanderbilt Initiative in Data-Intensive Astrophysics (VIDA) from Vanderbilt University
- NSF [AST-0349075, AST-0645416, AST 08-02230, AST-1056524, AST-0908816, AST-0705139]
- PAPDRJ CAPES/FAPERJ
- CAPES
- ESO
- CNPq [476909/2006-6, 474972/2009-7]
- FAPERJ [APQ1/26/170.687/2004]
- Pennsylvania Space Grant Consortium
- Alfred P. Sloan Foundation
- National Science Foundation
- Center for Exoplanets and Habitable Worlds
- Pennsylvania State University
- Eberly College of Science
- National Aeronautics and Space Administration
- W. M. Keck Foundation
- SDSS-III consortium
- NASA [NNX07AP14G]
- University of Florida
- Instituto Nazionale di Astrofisica (INAF), in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias (IAC)
- U.S. Department of Energy Office of Science
- University of Arizona
- Brazilian Participation Group
- Brookhaven National Laboratory
- University of Cambridge
- Carnegie Mellon University
- French Participation Group
- German Participation Group
- Harvard University
- Instituto de Astrofisica de Canarias
- Michigan State/Notre Dame/JINA Participation Group
- Johns Hopkins University
- Lawrence Berkeley National Laboratory
- Max Planck Institute for Astrophysics
- Max-Planck-Institute for Extraterrestrial Physics
- New Mexico State University
- New York University
- Ohio State University
- University of Portsmouth
- Princeton University
- Spanish Participation Group
- University of Tokyo
- University of Utah
- Vanderbilt University
- University of Virginia
- University of Washington
- Yale University
- Division Of Astronomical Sciences
- Direct For Mathematical & Physical Scien [849736] Funding Source: National Science Foundation
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We report the discovery via radial velocity (RV) measurements of a short-period (P = 2.430420 +/- 0.000006 days) companion to the F-type main-sequence star TYC 2930-00872-1. A long-term trend in the RV data also suggests the presence of a tertiary stellar companion with P > 2000 days. High-resolution spectroscopy of the host star yields T-eff = 6427 +/- 33 K, log g = 4.52 +/- 0.14, and [Fe/H] = -0.04 +/- 0.05. These parameters, combined with the broadband spectral energy distribution (SED) and a parallax, allow us to infer a mass and radius of the host star of M-1 = 1.21 +/- 0.08 M-circle dot and R-1 = 1.09(-0.13)(+0.15) R-circle dot. The minimum mass of the inner companion is below the hydrogen-burning limit; however, the true mass is likely to be substantially higher. We are able to exclude transits of the inner companion with high confidence. Further, the host star spectrum exhibits a clear signature of Ca H and K core emission, indicating stellar activity, but a lack of photometric variability and small v sin I suggest that the primary's spin axis is oriented in a pole-on configuration. The rotational period of the primary estimated through an activity-rotation relation matches the orbital period of the inner companion to within 1.5 sigma, suggesting that the primary and inner companion are tidally locked. If the inner companion's orbital angular momentum vector is aligned with the stellar spin axis as expected through tidal evolution, then it has a stellar mass of similar to 0.3-0.4 M-circle dot. Direct imaging limits the existence of stellar companions to projected separations <30 AU. No set of spectral lines and no significant flux contribution to the SED from either companion are detected, which places individual upper mass limits of M-{2,M-3} less than or similar to 1.0 M-circle dot, provided they are not stellar remnants. If the tertiary is not a stellar remnant, then it likely has a mass of similar to 0.5-0.6M(circle dot), and its orbit is likely significantly inclined from that of the secondary, suggesting that the Kozai-Lidov mechanism may have driven the dynamical evolution of this system.
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